#include <stdio.h>

void swap(int* x,int* y)
{
    int z = 0;
    z = *x;
    *x = *y;
    *y = z;
}

int main()
{
    int a = 10;
    int b = 20;
    swap(&a , &b);
    printf("a = %d,b = %d", a, b);
    return 0;

}